Field of the Invention
This invention relates, in general, to anesthetizers and, in particular, to a new and useful locking mechanism for the evaporators of anesthetizers.
The anesthetizers contain generally two evaporators in which various anesthetics are evaporated, and the vapor is then fed in adjusted amount to the respiratory system of the patient. In replaceable evaporators, which are simply suspended, a plurality of anesthetics may be available.
For safety reasons, it is necessary to provide a locking mechanism which prevents that the user accidentally opens either the wrong evaporator or both evaporators.
A Wknown locking system for an evaporator-anesthetizer with two evaporators has a three-way selector valve with which one of the evaporaors can be selected in its outside positions, while the other is locked in its zero position. Evaporator and selector valve are arranged at the front end of a distributor designed as a carrier which has an interior with respective gas paths. Each evaporator is suspended detachably by means of an angle over pairs of pins on the top side of the distributor. Gas apertures on the back of the evaporator are in contact with gas apertures at the front end of the distributor. On its top side are pivotally mounted two latches designed as rocking arms, which move against tension springs. In the stretched position, one end reaches behind the end of a locking flange on the adjusting knob of the respective evaporator and locks the latter in the zero position. In the relaxed position of the latch, the locking flange is free and the adjusting knob, hence the evaporator, can thus be freely operated. A link connected with the selector valve controls the latches at their other end, so that one latch is in the relaxed condition in the outside position, and the other is in the stretched condition. In the center position, both latches are in the stretched condition. This locking system is elaborate and susceptible to trouble, due to its many parts. The angle for the suspension of the evaporator must be introduced between a pair of retaining pins and the latch (DE-OS 30 58 564).
Another safety device for an anesthetizer with evaporators arranged in pairs is known which has the effect that one evaporator is locked when the other evaporator is in the open position.
Each evaporator has a rotating dial to determine the vapor concentration to be given off. The safety device contains a pair of reciprocating sensing pins and a swivel level cooperating with them. Each sensing pin is so arranged that it engages a cam recess in the dial when it is moved there by a corresponding swivel movement of the swivel lever. This dial is thus blocked and the evaporator cannot be connected.
The rotary movement of one dial causes automatically the sensing pin engaging the cam recess to move outside this cam recess, and causes a swivel movement of the swivel lever with which the other sensing pin is then introduced into the cam recess of the dial of the other evaporator. The mechanically relatively simple design permits only the use of anesthetizers with fixedly mounted evaporators. Its use with replaceable evaporators is not possible. (DE-OS 31 01 434).